create a name with runtime ((VAR)) so that everywhere the name is used
the pfa of the name's body is returned. This word is not immediate and
according to the ANS Forth documents it may get directly used in the
first part of a >DOES> defining word - in traditional forth systems
the word ><BUILDS was used for that and >CREATE was defined to be
the first part of a >VARIABLE word (compare with CREATE: and the
portable expression 0BUFFER:)